In term of video quality they're pretty much the same. Audio is better on the logitech one.
I would only use it for skype and maybe if my mic broke, then i would use the mic.
So it is not worth upgrading, yes?
For me it wouldn't be worth it no, but webcams are known to have shitty microphones.
I would just get a decent headset down the line and disable the mic on the webcam.